The present invention relates to terminal connecting devices for readily and securely connecting signal input/output terminals of a flexible substrate to those of an external substrate.
Large numbers of electronic components are incorporated in portable telephones, video cameras, and other electronic devices which are recently becoming increasingly smaller and lighter. Most components are mounted on substrates. To provide inter-substrate passage for electrical signals, flexible substrates are mostly used because of their light weight and versatility to form complex wiring. The following is some conventional methods to connect a flexible substrate to an external substrate:
(1) The flexible substrate has, either on its end or internally, signal input/output terminals which are secured to those of an external substrate by soldering.
(2) Signal input/output terminals 52 are provided at an end of a flexible substrate 51 as shown in FIG. 5. The terminals 52 are inserted and thus secured to a connector 55 on an external substrate 54.
(3) Japanese Laid-Open Patent Application No. 9-22760/1997 (Tokukaihei 9-22760; published on Jan. 21, 1997) discloses a structure in which signal input/output terminals 62 of a flexible substrate 61 contact a connector 63 with contact pins 64 on an external substrate 65 as shown in FIG. 6 to establish electrically conducting paths. The flexible substrate 61 is provided with engagement holes 61a with which engagement claws 63a of the connector 63 engage to secure the flexible substrate 61 onto the connector 63.
However, these methods entail following problems.
According to method (1), soldering is essential. In addition, prior to the soldering, the flexible substrate must be positioned precisely relative to the external substrate. In flexible substrates popularly used in recent years, the signal input/output terminals have so narrow intervals between them that the terminals makes a short circuit with an adjacent one even with a slight displacement in positioning. Therefore, extreme care is required in the positioning, which reduces operating efficiency. Besides, a solder and soldering iron need be prepared, as well as work space for the soldering operation. The flexible substrate must be removed to perform a maintenance operation and replace malfunctioning parts. In a worst case scenario, the external substrate, not to mention the flexible substrate, cannot be used again.
According to method (2), no soldering is necessary. Neither are preparations nor work space for it. The external substrate and the substrate can be used again. However, as shown in FIG. 5, the connector 55 must be mounted to the external substrate 54 in advance and a part of the external substrate 54 must be set aside in advance to attach the connector 55. In addition, typically, the connector 55 for use with flexible substrates requires the flexible substrate 51 to have a predetermined thickness on the back of the signal input/output terminals 52; a plate member 53 of a resin, for example, needs be attached to provide extra strength to it. Cost adds up due to additional labor and materials needed in positioning and combining operations to attach the plate member 53.
According to method (3), similarly to method (2), no soldering is necessary. Neither are preparations nor work space for it. The external substrate and the substrate can be used again. No plate member need be attached to provide extra strength to the flexible substrate 61. However, similarly to (2), the connector 63 with the contact pins 64 needs be mounted in advance to the external substrate 65 as shown in FIG. 6, and a part of the external substrate 65 must be set aside in advance to attach the connector 63. This entails expansion of the external substrate 65.
The present invention has a principal objective to offer terminal connecting devices for readily and securely connecting terminals of a flexible substrate to those of an external substrate, which allows for reduction in size of the external substrate by means of elimination of needs to use a connector and which can be manufactured at reduced cost.
A terminal connecting device for a flexible substrate in accordance with the present invention, in order to solve the problems, includes:
press means for connecting signal input/output terminals of a film-like flexible substrate provided with a wiring pattern to those of an external substrate by pressing the signal input/output terminals of the flexible substrate to those of the external substrate from a surface opposite to one where the signal input/output terminals of the flexible substrate are provided.
In the arrangement, the press means presses the signal input/output terminals of the flexible substrate from a surface opposite to one where those of the flexible substrate are provided, to establish connections between those of the flexible substrate and those of the external substrate.
This ensures establishment of electrically conducting paths between the flexible substrate and the external substrate.
For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings.